Device for lowering boats from ships



Dec. 2, 1924.

D. R. LJUNGMAN ET AL.

DEVICE FOR LOWERI NG BOATS FROM SHIPS Filed March 26 21 v INVENTQRS Dovud Richard Ljungman.

Fran s Danlgl Jun sson.

Patented es. 2, i924.

DAVID RICHARD LJ'UNGMAN AND BEANS DANIEL JANSSO'N, OF GOT'IENBORG, SWEDEN.

DEVICE FOR LO'WEBING BOATS FROM SHIPS.

Application filed March 26, 1921.

To all whom it may concern:

Be it known that we, DAVID R. LJUNGMAN and Frame DANIEL J ANSSON, subjects of the King of Sweden, and residents of Gotten- 6 borg, Sweden, have invented certain new and useful Improvements in Devices for Lowe-ring Boats from Ships, of which the following is a specification.

This invention relates to a ships davit,

and has for its objects to provide means for simultaneously rotating and axially moving a boom, by means of which a lifeboat is launched fully manned from its normal inboard position to a lowered outboard position; and to further provide means whereby the boom is automatically locked against further movement subsequently to a miximum outboard position of the boom having been reached.

The invention consists in the novel features of construction, arrangement and combinations of parts fully described in the following specification and set forth in the appended claims.

The preferred embodiment of the inven tion is illustratively exemplified in the accompanying drawing, in which: Fig. 1 is a side elevational view of our improved davit showing the boom in its outboard position, and in its inboard position in dotted lines; Fig. 2 is a substantially vertical sectional view through the supporting frame by means of which the boom is mounted to operate rotatably and axially thereof; Fig. 3 is a substantially longitudinal sectional view taken through the deck and showing the locking mechanism for the booms; Fig. 4 is a plan view of the ships deck showing the positions of and mechanism for locking the booms in position; Fig. 5 is a detail sectional view of the locking mechanism; Fig. 6 is a horizontal sectional view taken on the lines A--B of Fig. 5; Fig. 7 is a modified form of the looking mechanism shown in vertical section; Fig. 8 is a view taken on the lines A-B of Fig. 7 and Figs. 9 and 10 show a means for suspending the lifeboat from the booms.

Referring to the drawing, at denotes a boom having the usual curved upper portion and an extended lower portion projecting below the ships deck, as shown in Fig. 1. The mid portion of the boom a adjacent the ships deck is supported in a frame or standard 7) comprising a cylindrical upright section pro- Serial No. 455,771.

jecting portion adapted to support a roller (8 by means of a pivot pin 6 having its inner end threaded into the projecting portion of the collar 0 and the opposite end projecting through the roller 0?. With the collar 0 (Z carried by the former in a radius coniciding with the path of the guideway f, it will be noted that rotary movement of the boom a will" cause the roller (Z supported in the guideway fto travel to a lower or higher level with a consequent change in the elevation of the boom itself. The two possibleextremes to which the boom a may be moved are shown in Fig. 1, where the boom in its inboard position, shown in dotted lines, is held at ahigher level than when operated to its outboard position, as shown in full lines. These positions are determined by the relative location of the high and low points of the inclined guideway f with respect to the side of the ship. It is to be further understood, that inasmuch as there are two davits used for 'rigidy secured to the boom a and the roller each lifeboat and that the general rotation of each boom a to launch a boat is preferably towards the opposite davit, the higher section of the guideway will be on the side, of the standard I), which is farthest from the outboard side of the ship. This particular construction is designed to provide the greatest possible amount of support to the boom (1 during rotary movement of the latter towards the outboard side. In Figure 1 it is shown that the collar 0 is mounted on the lower portion of the boom a ma position to bring the roller (Z on the same side of the boom as the curve at the upper portion of the boom, in which case the strain of a load sus pended at the end of the boom 0, will tend to force the roller (Z downwardly against the lower wall or path of the guideway 7. There fore, instead of depending upon the base of the boom to take care of the great weight which is suddenly brought to bear against the axis of the boom, by the launching of a lifeboat, the mid portion of the boom is rigidly held in aligned position through the engagement of the roller (E with the surface or the guideway f.

To further strengthen the boom (1, against lateral displacement the upper end of the standard Z) is provided with a bearing cap or guide 5/ comprising a disc member having a central opening to receive the mid portion of the boom (L and av ball race in which a series of ball bearings is movable between the surface or" the boom and the wall ot the race. The cap carries a second s i it secured thereto and provided with a bearing plate It which embraces the boom a, and prevents water from entering the interior or the standard to freeze or o herwise endanger the operation of the parts. A spiral shaped cover plate '2 is secured to the edges of the walls of the guideways 7' to provide additional protection tor the interior oil the standard, against the elements. The extreme lower end of the boom (1 which pro jects below the ships decl: is mounted in a guide standard 5 secured to a sub-platiorm, the said guide being provided with a bearing cap similar to the corresponding part of the other guide 9 or the standard 7).

It is desirable especially during heavy weather at sea to provide the movable booms a with means for automatically locking them in either of their operative positions, i. e. outboard or launching position and inboard or deck position. in order to ii): the position or the boom aa locking mechanism, shown especially in Figures 3 and 4-. is provided, which comprises a sleeve Z secured to each boom a and a series of movable bolts 'H'L operating to check the vertical movement of the booms. The sleeve Z comprises a cyl' 1- drical member having upper and lower parallel flanges and a centrally disposed flange which is parallel to the other two flanges. The sleeves Z are of a diameter which permit both rotary and axial move ment thereof through an opening in the ships deck and through the space in the interior of the standard 5. In F igu re 3, it will be seen that a pair of oppositely arranged bolt guides are secured. to the underside of the ships deck closely adjacent each sleeve Z so that the bolts at when projected trom their respective guides by springs 11 will operate toward the axis of the sleeves Z and booms a. The inner ends of these bolts 12L are beveled in opposite directions, i. e. the left bolt will be inclined downwardly from its upper edge towards the rear while the other bolt will be inclined upwardly from its lower edge towards the rear. .l'n Figuie ii the mechanism for operating these bolts is illustrated and comprises a laterally movable connecting rod 0 extending through the outermost ends of the guides for the bolts m. The ends of the rod 0 are bent outwardly at right angles to provide arms 3) which are loosely secured to the rear ends of the outside bolts m. The inwardly projecting ends of the inside bolts m are similarly cminected to a pair of arms 2) carried by the rod 0 closely adjacent the inner ends of the bolt guides. In order to operate this rod 0 axially thereof to throw the bolts at out of engagement with the flanges of the sleeves Z, the rod is pivotally connected to one end of a bell crank lever carried by a bracket 2' mounted on deck. One arm or the lever 2'- is provided with a weight g which tends to hold the rod 0 in its adj" LGCl positions. It will be understood that the pivotal connection between the lever 1* and the rod o consists in providing the lower end the lever arm with a slot through which a pin carried by the rod projects.

in Figures 5 and 6, a modification or the locking device is shown having the roller (.5 mounted on one side of a sleeve Z which is provided with bolt receiving openings arranged in two levels, one above the other. The standard adjacent the path of movement of the sleeve Z is provided with a boss having a through bore to receive a bolt 2, the latter being beveled at its inner end, from the upper ed e thereof rearwardly towanls the under edge. In normal position (he bolt 2 is held in engagement with one oi" the openings in the sleeve Z a position which is brought about by a spring 3 yield ably held against the straight end oi. the bolt 2. The opposite end of the spring 3 is seated against a stop plug mounted in the outer end of the opening through the boss. It is desirable where only one bolt is used. to construct the latter so that it may be rotated to reverse the beveled end and thereby eilect a locking action when the boom may be moved axially in the opposite direction, i. c. upwardly to deck the lifeboat. In order that the cylindrical bolt 2 may not rotate when in operative position the latter is provided with oppositely disposed pins 5 movable in short keyways 6 cut into the inner surface of the boss. The space at the inner end of the keyways 6 permits the bolt to be rotated by withdrawing it until the pins 5 are clear of the .keyways, such an operation is effected by a handle 4 having a stem movable through the plug and attached to the straight end 01": the bolt 2.

Figures 7 and 8 illustrate a still further modified construction of the means for looking the boom a in position. This particular mechanism comprises a sleeve 7/ having longitudinal grooves into which the bolts 2 are projected. In this arrangement the bevel oi the bolt is disposed laterally instead of vertically as in the other terms.

In operation the davits operate as follows: Assuming a lifeboat is to be swung outboard it is first raised above the ships deck by means of a suitable block and tackle in the usual manner and then manned. The bolts m which have been engaged beneath the center flange of the sleeve Z are withdrawn by movement of the lever r and the booms a supported by the rollers d on the inclined paths f will descend simultaneously with the rotation of the boom as the rollers follow their respective paths. The booms a Will rotate toward each other and the lifeboat will swing outwardly over the side of the ship. During the axial movement of the boom and sleeve Z to a lower position the bolt on having the inclined end on its upper edge will slide over the center flange oi the sleeve and enter the upper groove in the latter. In this position the boom 0, will be locked against movement to return to its inboard position. This feature is very important in a heavy rolling sea where a sudden inclination of the ship will have a tendency to swing the lifeboard deckward, in which case should there be no means or preventing such a movement oi the boat and booms the former would be dashed to pieces. To return the booms to their normal inboard positions the lever 1" is moved to the opposite side of the pivot and the rod 0 will operate to withdraw the engaging bolts am through the arms n.

In the modifications of the locking mechanism shown in Figures 5 to 8, the bolts 2 and 2 are operated by handles 4: which are yieldably withdrawn against the springs 3 to release the sleeves Z and Z and then rotated to engage the ends against the bolt receiving openings in the sleeves.

Having fully described the invention and disclosed the general operation of the several parts, what We claim and desire to secure by Letters Patent is:

1. In a ships davit, the combination with a supporting member having an inclined guideway and an axial bearing, of a boom mounted in said bearing and projecting axially through said member, said boom being provided with a roller movable in said guideway to simultaneously operate the boom in a rotary and axial direction, and a locking mechanism for the boom and comprising a flanged sleeve movable with the boom and oppositely proj ecting bolts movable into and out of the path of the axial movement of the said sleeve to lock the latter in its extreme axial positions.

2. In a ships davit, the combination with a rotatable and axially movable boom, of an automatically operated mechanism for engaging the said boom at its maximum axial positions, said mechanism comprising a grooved sleeve secured to said boom and movable therewith, a pair of oppositely beveled bolts yieldably directed towards the axis of said boom and into the path of the said sleeve, and means for operating the bolt against the yieldable support to Withdraw the former out of the path of movement of the sleeve to permit axial movement of the latter.

In testimony whereof, we have signed our names to this specification in the presence of two subscribing witnesses.

DAVID RICHARD LJUNGMAN. FRANS DANIEL JANSSON. Witnesses: a

CLAiis As'rRoM, Orion WALLs'rRoM. 

